xref: /aosp_15_r20/external/skia/docs/examples/Image_scalePixels.cpp (revision c8dee2aa9b3f27cf6c858bd81872bdeb2c07ed17)
1 // Copyright 2019 Google LLC.
2 // Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
3 #include "tools/fiddle/examples.h"
4 REG_FIDDLE(Image_scalePixels, 256, 128, false, 3) {
draw(SkCanvas * canvas)5 void draw(SkCanvas* canvas) {
6     std::vector<int32_t> srcPixels;
7     int quarterWidth = image->width() / 16;
8     int rowBytes = quarterWidth * 4;
9     int quarterHeight = image->height() / 16;
10     srcPixels.resize(quarterHeight * rowBytes);
11     SkPixmap pixmap(SkImageInfo::MakeN32Premul(quarterWidth, quarterHeight),
12                     &srcPixels.front(), rowBytes);
13     canvas->scale(4, 4);
14 
15     const SkSamplingOptions samplings[] = {
16         SkSamplingOptions(),
17         SkSamplingOptions(SkFilterMode::kLinear),
18         SkSamplingOptions(SkFilterMode::kLinear, SkMipmapMode::kLinear),
19         SkSamplingOptions({1.0f/3, 1.0f/3}),
20     };
21     for (unsigned index = 0; index < std::size(samplings); ++index) {
22         image->scalePixels(pixmap, samplings[index]);
23         sk_sp<SkImage> filtered = SkImages::RasterFromPixmap(pixmap, nullptr, nullptr);
24         canvas->drawImage(filtered, 16 * index, 0);
25     }
26 }
27 }  // END FIDDLE
28